North Atlantic storm

38°14.9′N 056°33.9′W

Waves left about 28 Sep 15:43Z, ± 3 h

Placed by 5 buoys, whose own placements lie within 284 nmi of it

Each buoy places the storm from how its swell's period shortened as it arrived: the longest waves travel fastest. Fronts are drawn at deep-water group speeds along great circles, and stop at land. How it is worked out